Magnesium halides complexes

Chelating diethers such as DME and 1,4-dioxane are useful, but their use tends to result in precipitation of a magnesium halide complex this phenomenon is made use of in the most commonly used procedure for obtaining solutions of dialkylmagnesium compounds. 

The rapid precipitation of magnesium halide complexes when bases such as dioxan are added to Grignard reagents shows that exchange processes occur ... 

The 1 l)5-hydroxyl group in the A -3-ketone (33) favors attack towards the j -face of the molecule, possibly due to complex formation with the methyl-magnesium halide. Thus, the )5-methyl isomer (34), is obtained as the major product in 22% yield after reacetylation. 

Magnesium forms few halide complexes of the type MX4 , though [NEt4]2[MgCl4] has been reported examples of for the heavier... 

Highly reactive calcium can be readily prepared by the reduction of calcium halides in tetrahydrofuran solution with preformed lithium biphenylide under an argon atmosphere at room temperature.5 This colored calcium species seems to be reasonably soluble in THF. However, the reactive calcium complex prepared from preformed lithium naphthalenide was insoluble in THF solution and precipitated out of solution to give a highly reactive black solid. The exact nature of this black calcium complex has not been determined. Acid hydrolysis of the black material releases naphthalene as well as THF. Accordingly, the most likely structure of the black material is a Ca-naphthalene-THF complex similar in nature to the soluble magnesium-anthracene complex recently reported.6... 

Phosphinimido trichloro complexes, with Ti(IV), 4, 361 Phosphinimines, magnesium halide reactions, 2, 88 0-Phosphinoalkoxo ligands, on mono-Cp Ti(IV) complexes, 4,487... 

This is a direct SN2 displacement of a bromide anion by a phenyl anion. Please note that the negative charge of the phenyl anion is accompanied by a magnesium bromide complex. This class of organic salt is known as a Grignard reagent and is characterized by the presence of magnesium and a halide such as chloride, bromide, or iodide. 

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